In recent years, in order to hasten the time of delivery as well as to improve the productivity of finished photographic prints, in the photographic light-sensitive material for making prints, there are adopted a method of using a silver halide having a high silver chloride content that is fast developable for rapid processing and a method of raising the sensitivity of the light-sensitive material for shortening the duration of making prints. However, it is virtually impossible to raise the sensitivity of silver chloride because silver chloride tends to easily fog when its sensitivity is tried to be raised or its characteristics are liable to change with time during its storage.
In order to get rid of such the disadvantage of a high-silver-chloride-content silver halide emulsion, various techniques have been disclosed to date. For example, as techniques for increasing the speed of a high-silver-chloride-content silver halide emulsion JP O.P.I. Nos. 95736/1983, 108533/1983, 222844/1985 and 222845/1985 describe that a high-speed emulsion with little fog can be obtained by making a high-silver-bromide-content phase locally present inside the grain or as a surface phase of the grain. According to the investigation by us, the inventors of the invention, however, these techniques surely enable to increase the speed of the emulsion, but make the characteristics thereof very liable to be affected by changes in processing solutions, so that it is hard to make photographic prints of a consistent quality.
JP O.P.I. Nos. 153536/1988 and 86135/1989 describe that the addition of a gold compound to an emulsion in the process of its chemical sensitization makes it possible to highly sensitize the emulsion. As a result of our investigation, it has been found that the above is a suitable sensitization method for the high-silver-chloride-content silver halide emulsion because it makes the emulsion highly sensitive, less fogged and stable against processing solutions. However, a light-sensitive material comprising an emulsion highly subjected to gold sensitization treatment showed a phenomenon of a difference in the sensitivity and gradation between when processed immediately after being exposed and when processed with an intermission after being exposed (the phenomenon is hereinafter referred to as short-time latent image fluctuation). This phenomenon is a behavior peculiar to high-silver-chloride-content silver halide emulsions, which, when the exposure/development interval in the print-making process in minilabs is irregular, largely affects the quality of finished photographic prints, thus being a large stumbling block to making the high-silver-chloride-content light-sensitive material a practical reality. Further, the light-sensitive material comprising a high-silver-chloride-content silver halide emulsion subjected to gold sensitization treatment has the disadvantage that it tends to become fogged during its aging storage after being prepared, e.g., when stored under high temperature/high humidity conditions.
In order to improve the aging stability of the photographic characteristics after exposure of the light-sensitive material, JP E.P. No. 56969/1988 discloses a method for incorporation of a high-molecular benzenesulfinic acid compound into the light-sensitive material. Further, JP O.P.I. No. 113236/1985 discloses the incorporation of an imino group-having compound into the light-sensitive material. These methods, however, have been found to have no effect at all on the improvement of the photographic characteristics fluctuation in a very short time after exposure.
As a result of our continued investigation on the above phenomenon, it has been found that by separately effecting the sulfur sensitization process and the gold sensitization process described in JP O. P. I. No. 136143/1989 to make chemical sensitization, the light-sensitive material can be improved on its short-time latent image fluctuation with its high sensitivity being kept intact. However, no improvement is made on the fog increase during aging storage attributable to the gold sensitization.
In order to restrain the light-sensitive material from fogging during its aging storage, it is known to have the light-sensitive material contain various compounds for example, U.S. Pat. Nos. 2,403,927, 3,266,897 and 3,708,303, JP O.P.I. Nos. 135835/1980 and 71047/1984 describe the incorporation of mercaptotetrazoles, mercaptotriazoles or mercaptodiazoles, but their improving effect is not enough for practical use because their fog-restraining capacity is small and when used in a large amount, they cause desensitization of the light-sensitive material.